I could imagine a historic drama
Something like a
Conspiracy-type production would be good, as long as you could get the budget for it. You'd certainly need exceptionally good writers and historical consultants.
very high-minded conversations while dinner
Palmerston had quite the appetite. When he entertained the Speaker at the start of the 1865 Parliamentary session, he had:
1) Two plates of turtle soup
2) A plate of cod and oyster sauce
3) Paté
4) Two 'very greasy-looking' entrées
5) Roast mutton
6) 'the largest, and to my mind the hardest, slice of ham that ever figured on the table of a nobleman'
7) Pheasant
8) A pudding
9) A jelly and a glass of sweet champagne
10) Dressed oranges, half a large pear, and a glass of sherry.
I'm not sure how much time this would leave for conversation, high-minded or otherwise.
Maybe even discuss palmerston´s cool response regarding the Trent-affair.
There wouldn't be much to argue about in respect of the Trent- Lincoln, after all, had admitted at the time that he couldn't argue against Seward's position, while Palmerston had complained bitterly about the Conservative government's decision to stop exercising the right of visitation on US-flagged ships in 1858, so the two were perhaps closer on the issue than their respective national stances would suggest. I think the most interesting discussions might have come in the 1848-51 period, while Palmerston was foreign secretary advocating the cause of liberalism on the continent and Lincoln was an ex-Congressman contemplating slavery and militarism. Having it before the civil war also avoids a significant quantity of the bad blood that might otherwise have existed between the two. It'd take some significant changes, but you might get Lincoln the "envoy extraordinary and minister plenipotentiary" position that historically went to Abbott Lawrence, or a more minor post in the US diplomatic mission.
The unfortunate thing is that the best description we have of Palmerston's diplomatic functions comes from Henry Adams, who by his own admission was an extremely lonely, isolated and unhappy young man. His depiction of his time in the UK is steeped in this unhappiness:
Far down the staircase one heard Lord Palmerston's laugh as he stood at the door receiving his guests, talking probably to one of his henchmen, Delane, Borthwick, or Hayward, who were sure to be near. The laugh was singular, mechanical, wooden, and did not seem to disturb his features. "Ha! ... Ha! ... Ha!" Each was a slow, deliberate ejaculation, and all were in the same tone, as though he meant to say: "Yes! ... Yes! ... Yes!" by way of assurance. It was a laugh of 1810 and the Congress of Vienna. Adams would have much liked to stop a moment and ask whether William Pitt and the Duke of Wellington had laughed so; but young men attached to foreign Ministers asked no questions at all of Palmerston and their chiefs asked as few as possible.
I suspect that, had Lincoln and Palmerston met, they might have interacted quite well. Both were adept at using humour- Marx described Palmerston as:
Possessed of a wonderful memory, of great experience, of consummate tact, of never-failing presence of mind, of gentlemanlike versatility, of the most minute knowledge of Parliamentary tricks, intrigues, parties, and men, he handles difficult cases in an admirable manner and with a pleasant volatility... Being an exceedingly happy joker, he ingratiates himself with everybody. Never losing his temper, he imposes on an impassioned antagonist. When unable to master a subject, he knows how to play with it.
It's unlikely they would ever have been friends. However, Lincoln doesn't strike me as the kind of person to give diplomatic answers to a question instead of honest ones, while Palmerston could never resist an opportunity for banter. Whenever he was in Tiverton addressing his constituents, he invariably used to get in a verbal spat with a local Chartist butcher called Rowcliffe. It could have been an interesting period, if a slightly fraught one from the point of view of Anglo-American relations, as the two of them verbally jousted.